Survey of soybean oil and meal qualities produced by different processes

Soybean oil and meal produced by extruding-expelling (E-E) are believed to have unique characteristics compared with products produced by solvent extr action (SE). A survey was conducted to compare quality characteristics of t he;oils and meals produced from different types of soybean processing metho ds. Soybean oil and meal samples were collected three different times withi n a l-yr period from 13 E-E mills, 8 SE plants, and 1 continuous screwpress (SP) plant. Properties of oil and meal varied considerably between differe nt types of plants and among plants of the same type and sampling times. In general, settled crude E-E and SP oils had significantly greater peroxide values than those of SE oils. E-E oils contained less free fatty acid and p hosphorus than did SE and SP oils. The oxidative stability (AOM) of E-E oil was less than that of SE oil, and that of SP oil was intermediate. E-E and SP meals had higher oil and lower protein and moisture contents than those of SE meals. Protein dispersibility indices were lower for E-E and SP meal s. Protein solubilities in KOH were similar for E-E and SE meal, but higher than that of SP meal (62%). Rumen bypass protein values were higher for th e SP meal.